Compact Autonomous Measuring System for Large Membrane Mirror
Abstract
Principal and functional schematics of a liquid-crystal (LC) Hartmann wavefront sensor and two-wavelength dynamic holographic interferometer capable of measuring severe aberrations up to 2000 micrometers are proposed. The LC Hartmann sensor can be implemented in different versions including Shack LC lenslet array, large focusing LC tunable lens or LC hole array. The simplest controllable LC hole array was manufactured and is under calibration at the moment. The two-wavelength holographic interferometer allows one to test large aberrations in visible range with the help of conventional detector arrays as an interference pattern to be analyzed is formed at an equivalent wavelength much more than the wavelength of the radiation of the initial beams used. The main issue is a recording medium possessing high spatial resolution up to 1000 mm-1. An optical set up for measuring the diffraction efficiency of holographic media, in particular, liquid-crystal spatial light modulators, was assembled. The investigations are in progress now. A preliminary comparison of both methods under investigations is given on the basis of the most important criteria (dynamic range, simplicity, possibility of real-time operation etc.). It is pointed out that additional experiments are needed using a 212 mm membrane mirror manufactured in the scope of the study. A summary table of the considered method is presented including the main advantages and drawbacks of the method. Practical comments and recommendations on the implementation of the devices developed and some proposals on the follow-on of the work are given.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2000
- Accession Number
- ADA379165
Entities
People
- Vadim A. Parfenov